It is my understanding that many bear hunters carry some kind of handgun as a back-up in the event an encounter gets up close and personal. 44 magnum and 454 Casull are popular calibers, from what I’ve heard.
Some do I like handguns and have one with no matter what I am hunting. Be it bears or squirrels because I like handguns and I can.
My normal handgun when out bear hunting is a TI. 41 mag or a Ruger 44 red hawk.
Can’t go wrong with a Ruger revolver. I have 3 of them - all single action, though.